Well, lets try to understand a few things.
An INverter turns 12V DC into 120V AC, thats for things like your outlets, AC etc.
A Converter turns 120V into 12VDC to charge your batteries and run things like your 12V lights, furnace etc.
All trailers come with a converter.
Some trailers come with a inverter. Are you sure yours has an inverter? And if it does, for it to automatically switch over when you loose AC power you als need what is called a "transfer switch". Otherwise you need to turn on the inverter manually.
There is a high likelyhood that your trailer doesn't have an inverter so when you loose power anything that runs off 120V won't work. Things like the AC, TV (sometimes) microwave,
And without power your batteries will run the 12V appliances for while, until the batteries get low.
